Knocking type sound at Idle

[Lyds]

Hey guys, first post here since I got my CPO '06 A4 28,000 miles- been browsing for a while though :) I did a search and couldn't find anything that pertained to the issue that I am having.

Bought my car in November of '07 and had a few problems when I first purchased it, but I love the car and have been relatively problem free since the initial instances. First the coil-packs needed to be replaced 3 days after I picked it up. Got the car back, needed a new fuel pump a week later. And finally the wind shield started leaking above the rear view mirror... Luckily the dealership I purchased the car from is down the street from my house and has been very helpful with fixing the problems and giving me a loaner car free of charge.

Fast forward a month - I started to hear a knocking type noise after the car has fully warmed up. When the engine is cold/fresh start it sounds perfectly, little noisy but I guess thats normal for our engines. When the engine is warm and has been driven for about 5 miles there you can hear a very audible knocking sound, almost sounding like a diesel, coming from the engine.

I brought the car into the dealership to have them investigate, had the service manager come out and listen to the noise before I left so he knew what I was referring to, and he agreed there was a problem. Got a phone call 3 days later from the dealership stating that they heard the problem, but checked everything mechanical and everything was working fine. I was told not to worry about the noise.

Now, one month later the noise is even more audible. Has anyone else experienced this kind of noise? It puzzles me because the noise is only audible after the car is fully warmed up and has been driven for a few miles. Any clue what the problem could be so I can take it back to them and get it fixed?

~Lyds

C/N: Bought car in November, had a few problems nothing major. Now have a audible knocking type sound @ idle after warm up. Dealer says nothing mechanically wrong, but the noise is abnormal any advice ?

[konijay]

Is it ticking sound? like Tick tick tick....?

If it is, it's normal

[Lyds]

When I had the A4 loaner they gave me I did not notice the same noise. I know the injectors/fuel pump on this car is noisy, and it definitely does not sound like the ticking noise that they make.

[Zebman]

You are putting 91+ octane in it, correct?

It could be a slew of problems, hopefully it is injector-related.

[Lyds]

Since i purchased it, I have never put anything under 93 in it.

[Jersey Stephen]

why do are cars make the tick tick tick sound?

[RisR32]

is it a man. transmission.... could be the fly wheel... I had a similar issue on my .:R once I replaced it, no more ticking on idle.

[Lyds]

It is a manual transmission, but its not a ticking noise. What confuses me is that the noise is not there when the car is cold, just when fully warmed up.

[SilverB7FL]

I was told it was the emissions purging. My car does the same thing except I get it up front near the engine and also in the back near the gas tank.

[Sharkfin]

the ticking is normal, most people think it is the valve sticking usually happens because you don't use premium gas but its normal for audi whether you do or not, sounds like a diesel...

[4-tified]

It is a manual transmission, but its not a ticking noise. What confuses me is that the noise is not there when the car is cold, just when fully warmed up.

If it were a throw-out bearing, you can make the noise come and go by simply pushing the clutch pedal in and out.
If that's not it, then it's not the T-O bearing.

Our FSI engines do sometimes sound a bit like a diesel.
Granted, it's not the heavy knock sound of diesel fuel detonating, but the FSI does have this low "knock" type sound.
This has been talked about by car writers and owners even since the FSI came to market. I don't know if earlier engines tend to have a more pronounced "knock" sound than newer FSI engines, but it seems to be pretty normal.
The sound is caused by the direct injected fuel and the relatively high compression ratio for a turbo charged engine.

My 06 2.0T, manual has that odd low "rumble" or "knock", but it's not like an actual metallic knock sound per se, just an odd low tone.
When the engine is cold the rpm is higher and overall engine noise volume is greater, thus you don't hear the lower pitched tones, and due to higher rpm, there simply may be less actual "knock" sound generated.
As you drive and engine speed increases you notice the overall engine tone change, and no knock sounds. I do find that there is a kinda cool low pitched "growl" as the engine accels past 4k rpm. I like it.

From everything I've read and heard about the FSI, I don't think it's a problem. If what you hear is a VERY audible metallic "knocking" sound, then the Audi dealer needs to look deeper into the issue. If it's a general low volume sound, it's probably normal.

The loaner you got, it to is a manual? If not, then it's a different comparison, although you could put an auto in "park" and then the engine will idle nearly the same.
Plus, as I said, perhaps the newer FSI engines are a bit quieter.
I've driven a few A3 2.0's auto and manual, and some automatic A4 2.0's.
Some had the more pronounced low rpm "knock" sound of like my 2.0, some less, and a couple that sounded a bit louder.

When was the last time the engine had an oil and filter change?
Also, the weather is quite a bit colder now. Has the sound become different in the winter compared to when it was warmer?

The distinctly different "ticking" sounds are not the low rpm "knock" sound.
Ticking sounds in the engine are usually the fuel injectors and/or the self adjusting hydraulic valves.
Injectors have the tick, which is a normal part of their function, some are louder than others.
The valve lash adjusters can tick due to not enough oil pressure built up to fully set the valve lash.
They can tick due to varnish/gunk build up inside the oil hole, thus the adjusters can't adjust fully.
Sometime tick can be heard and described by some as a "knocking" sound.

This sound can occur when the engine is cold and oil pressure had not built up in the adjuster yet and thus the valve lash is a bit off.
As the engine warms the oil pressure in the adjuster rises and things quite down.
If the noise starts when the engine is warm, then it could be that the adjusters are dirty/varnished, and that might be due to too long of an oil drain interval. Since you bought it used, it would be good to see the maintenance record.
Also, you can get a ticking problem that pops up when the engine is warm, but not when it's cold, when a too light weight oil is used for the environment.
When cold the oil has a certain viscosity that can pressurize the adjusters normally. But, when the oil heats up the viscosity can decrease and the oil becomes too thin to keep the oil pressure up in the adjusters. If the pressure drops in the adjusters then the valve lash can be off and a ticking noise can happen.
So, too thick or too thin oil can cause the ticking noise too.

Try an oil change with a good FULLY synthetic oil in the correct viscosity range for your atmospheric conditions and see if that calms things down.

[acidrome]

^ agree. FSI tend to sound like diesel. So it may be normal,

[Lyds]

The noise is there regardless of whether the clutch is depressed or not, so i dont believe its the T-O Bearing.

The actual volume of the sound is quite audible. I guess the best way to describe the volume is that sitting inside the car, if the radio is under volume #6 I can hear the sound still. As to the sound, it sounds metallic, definitely not a ticking type sound.

The loaner i received was also a manual with a 2.0T engine.

And the oil and filter was last changed about 2,000 miles ago.

[acidrome]

take it in if u must? im sure they will have a better idea if u dont fels its normal

[Lyds]

take it in if u must? im sure they will have a better idea if u dont fels its normal

Therein lies the problem. I took it to the dealer, they said the sound was abnormal, but failed to diagnose the problem after 3 days of having the car. They said everything is mechanically sound. Guess ill just have to take it to a different dealership and see if I have any luck there.

[acidrome]

wow thats wierd, but ya i guess take to another dealer now if they say they same then i guess ur goin to have to take their advise

[joshd2012]

Our FSI engines do sometimes sound a bit like a diesel.
Granted, it's not the heavy knock sound of diesel fuel detonating, but the FSI does have this low "knock" type sound.
This has been talked about by car writers and owners even since the FSI came to market. I don't know if earlier engines tend to have a more pronounced "knock" sound than newer FSI engines, but it seems to be pretty normal.
The sound is caused by the direct injected fuel and the relatively high compression ratio for a turbo charged engine.

My 06 2.0T, manual has that odd low "rumble" or "knock", but it's not like an actual metallic knock sound per se, just an odd low tone.
When the engine is cold the rpm is higher and overall engine noise volume is greater, thus you don't hear the lower pitched tones, and due to higher rpm, there simply may be less actual "knock" sound generated.
As you drive and engine speed increases you notice the overall engine tone change, and no knock sounds. I do find that there is a kinda cool low pitched "growl" as the engine accels past 4k rpm. I like it.

From everything I've read and heard about the FSI, I don't think it's a problem. If what you hear is a VERY audible metallic "knocking" sound, then the Audi dealer needs to look deeper into the issue. If it's a general low volume sound, it's probably normal.

It definitely freaked me out the first time I drove an Audi. I couldn't believe how loud the engine was compared to my last four banger. I found out it was normal, but it still throws me for a second every time I put down the window and don't have the sound muffled by my firewall.

That said, I did come across a used A4 that had a metallic sound at idle, but it was constant. The car was noticeable louder than other Audis, even side-by-side you could hear the difference. It sounded like something was hitting every time the engine cycled. I mentioned this to the dealership, and they said they had gotten that same comment a few times about that car. They didn't know why, though.

[Lyds]

That said, I did come across a used A4 that had a metallic sound at idle, but it was constant. The car was noticeable louder than other Audis, even side-by-side you could hear the difference. It sounded like something was hitting every time the engine cycled. I mentioned this to the dealership, and they said they had gotten that same comment a few times about that car. They didn't know why, though.

That sounds exactly like I am talking about, except the sound was not there until after I purchased the car.

I'm just getting antsy because I want to start modding, but I want to make sure everything is sound before I start doing anything.

[TSlice]

Just make sure you are on record with your dealer as reporting the problem and having them not be able to diagnose it so you won't have any problems as far as warranty goes if something were to go wrong.

[SilverB7FL]

I have a 05.5 and I had to get an 08 loaner and that A4 was def. alot quieter engine wise then mine, it also didn't have the horrible vibration at idle like mine does

[trueno429]

i noticed that it was EXTREMELY loud tonight when i got done driving my car during idle...i noticed the sound too when i got the car used a few months back and i also noticed that it only makes the sound when ive been driving for a while..tonight i drove for 2 straight hours and it made alot of noise..maybe our engines just needs to cool down

[B7A4AWD]

Does this thumping/knocking noise sound like its coming from the front or back of the car. Does it sound rythematic or is it random?

[Kinch]

LYDS, I'm in the same boat. Purchased a CPO 06' 2.0T in January 08'. Just got back from my second visit to the dealer for the engine ticking. First time they found nothing. Second time they replaced the fuel pump. No change to the very loud ticking that stands out at idle. My 08' loaner sounded fine...

[cecaa]

If it were a throw-out bearing, you can make the noise come and go by simply pushing the clutch pedal in and out.
If that's not it, then it's not the T-O bearing.

Our FSI engines do sometimes sound a bit like a diesel.
Granted, it's not the heavy knock sound of diesel fuel detonating, but the FSI does have this low "knock" type sound.
This has been talked about by car writers and owners even since the FSI came to market. I don't know if earlier engines tend to have a more pronounced "knock" sound than newer FSI engines, but it seems to be pretty normal.
The sound is caused by the direct injected fuel and the relatively high compression ratio for a turbo charged engine.

My 06 2.0T, manual has that odd low "rumble" or "knock", but it's not like an actual metallic knock sound per se, just an odd low tone.
When the engine is cold the rpm is higher and overall engine noise volume is greater, thus you don't hear the lower pitched tones, and due to higher rpm, there simply may be less actual "knock" sound generated.
As you drive and engine speed increases you notice the overall engine tone change, and no knock sounds. I do find that there is a kinda cool low pitched "growl" as the engine accels past 4k rpm. I like it.

From everything I've read and heard about the FSI, I don't think it's a problem. If what you hear is a VERY audible metallic "knocking" sound, then the Audi dealer needs to look deeper into the issue. If it's a general low volume sound, it's probably normal.

The loaner you got, it to is a manual? If not, then it's a different comparison, although you could put an auto in "park" and then the engine will idle nearly the same.
Plus, as I said, perhaps the newer FSI engines are a bit quieter.
I've driven a few A3 2.0's auto and manual, and some automatic A4 2.0's.
Some had the more pronounced low rpm "knock" sound of like my 2.0, some less, and a couple that sounded a bit louder.

When was the last time the engine had an oil and filter change?
Also, the weather is quite a bit colder now. Has the sound become different in the winter compared to when it was warmer?

The distinctly different "ticking" sounds are not the low rpm "knock" sound.
Ticking sounds in the engine are usually the fuel injectors and/or the self adjusting hydraulic valves.
Injectors have the tick, which is a normal part of their function, some are louder than others.
The valve lash adjusters can tick due to not enough oil pressure built up to fully set the valve lash.
They can tick due to varnish/gunk build up inside the oil hole, thus the adjusters can't adjust fully.
Sometime tick can be heard and described by some as a "knocking" sound.

This sound can occur when the engine is cold and oil pressure had not built up in the adjuster yet and thus the valve lash is a bit off.
As the engine warms the oil pressure in the adjuster rises and things quite down.
If the noise starts when the engine is warm, then it could be that the adjusters are dirty/varnished, and that might be due to too long of an oil drain interval. Since you bought it used, it would be good to see the maintenance record.
Also, you can get a ticking problem that pops up when the engine is warm, but not when it's cold, when a too light weight oil is used for the environment.
When cold the oil has a certain viscosity that can pressurize the adjusters normally. But, when the oil heats up the viscosity can decrease and the oil becomes too thin to keep the oil pressure up in the adjusters. If the pressure drops in the adjusters then the valve lash can be off and a ticking noise can happen.
So, too thick or too thin oil can cause the ticking noise too.

Try an oil change with a good FULLY synthetic oil in the correct viscosity range for your atmospheric conditions and see if that calms things down.

4-tified had very impressive answer! thanks

[tribe]

That could be a rod knocking. You can buy a cheap stethoscope at a CVS and listen to your engine and localize the exact place of the knocking.

Since the coils and the fuel pump went south shortly after you got it, you can presume that the car has been used hard.

Good Luck

[Unleaded20T]

tic tic noise its normal, but a knocking noise could be a lot of things, most common is bad valve/s.

[gyroscope]

The ticking noise is normal for these engines. Mine does the exact same thing. Sounds like my fathers TDI. It's the FSI injectors snapping the fuel into the engine.

[OceanBlueB7]

Exhaust leak perhaps?